Knaresborough bus station was the only area in the district to record a yearly rise in nitrogen dioxide levels between 2019 and 2021.
Nine out of all 64 monitoring locations saw an increase during the same period, although each had a drop during 2020 when lockdowns led to tight restrictions on travel.
All locations remain below current legal limits, but these targets are set to be reduced by the government after warnings that pollutants are even more dangerous than previously thought.
Air pollution is associated with a number of serious health impacts - it particularly affects the most vulnerable, including children and older people, and those with heart and lung conditions.
The latest figures for Harrogate have been revealed in a report from the borough council which shows nitrogen dioxide levels rose from 2019 to 2021 at:
- Station Parade taxi rank, Harrogate
- Harlow Crescent, Harrogate
- Devonshire Place, Harrogate
- Woodfield Road, Harrogate
- High Skellgate, Ripon
- High Street, Knaresborough
- Knaresborough bus station
- The Royal Oak, Knaresborough
- Bond End, Knaresborough
Bond End is one of four Air Quality Management Areas (AQMAs) declared by the council for previously breaching the legal limit of 40 micrograms of annual nitrogen dioxide per cubic metre of air.
The figure for Bond End, which has had traffic light upgrades to tackle pollution from idling vehicles, now stands at 38.3 - the highest in the district.
For the first time in 15 years, the World Health Organisation (WHO) last year released new guidelines which mean the UK's legal limits for the most harmful pollutants are now four times higher than the maximum levels recommended.
This is after research found air pollution from areas including vehicle exhausts and gas central heating is having a big impact on health, even at lower concentrations.
While not legally binding, the WHO guidelines are used as reference tools by policymakers around the world and impact on how legal limits are set.
The UK government has yet to approve new limits, with a bill currently going through the legal process.
If the WHO's new target of 10 micrograms of annual nitrogen dioxide per cubic metre of air is introduced, just two locations in Harrogate would meet the new guidelines.
In its annual report, Harrogate Borough Council said it had no plans to declare any new AQMAs under the current rules, but added it recognised there was work to do to improve air quality.
It said: "Concentrations have risen across the district in 2021, but this is following 2020 when there were multiple lockdowns.
"Whilst air quality has improved significantly in recent decades, and will continue to improve due to national policy decisions, there are some areas where local action is needed to improve air quality further.
"We work with colleagues within the highways, sustainable transport and public health departments at North Yorkshire County Council on air quality, and will continue to do this to improve local air quality."
By Jacob Webster, Local Democracy Reporter